A new quantity for studies of dijet azimuthal decorrelations

Abstract

We introduce a new measurable quantity, $R_{\hat{I}”\ddot{I}•}$, for studies of the rapidity and transverse momentum dependence of dijet azimuthal decorrelations in hadron-hadron collisions. In pQCD, $R_{\hat{I}”\ddot{I}•}$ is computed as a ratio of three-jet and dijet cross sections in which the parton distribution functions cancel to a large extent. At the leading order, $R_{\hat{I}”\ddot{I}•}$ is proportional to $\hat{I}{\pm }_s$, and the transverse momentum dependence of can therefore be exploited to determine $\hat{I}{\pm }_s$. We compute the NLO pQCD theory predictions and non-perturbative corrections for $R_{\hat{I}”\ddot{I}•}$ at the LHC and the Tevatron and investigate the corresponding uncertainties. From this, we estimate the theory uncertainties for $\hat{I}{\pm }_s$ determinations based on $R_{\hat{I}”\ddot{I}•}$ at both colliders. The potential of $R_{\hat{I}”\ddot{I}•}$ measurements for tuning Monte Carlo event generators is also demonstrated.

20 pages, 11 figures, 1 table, submitted to JHEP